Conventional multi-slide coating apparatus perform coating operations by metering individual layers of a coating fluid from a supply source, through a trough disposed inside a hopper, and then through a narrow distribution slot. A coating fluid is distributed by the slot as a layer uniformly across a downwardly inclined surface of a slide. The layer of coating fluid flows by gravity down the slide surface and meets with adjacent underlayers of coating fluid which have been similarly metered and distributed through narrow slots. The combined layers of coating fluid then flow down the slide surface and form a coating bead. A web to be coated is carried by a backup roll and passes across the bead. The fluid layers in the bead impinge upon the moving web which picks up the multiple fluid layers from the slide surface. Illustrative slide coating apparatus are disclosed in U.S. Pat. No. 2,761,417, U.S. Pat. No. 3,289,632, U.S. Pat. No. 4,283,443, and U.S. Pat. No. 4,443,504.
In a coater facility, the slide coating apparatus includes at least two plates to form a fluid supply cavity, i.e., hopper, trough, and distribution slot. Typically, several plates are used to supply multiple fluids to the slide surface. In coating photosensitive materials, it is frequently necessary to separate the plates and clean the cavity area between each of the plates, such as when a different photosensitive formulation is to be coated or when there is an accumulation of hardened or dried solution retained or caught in the cavity. It is desirable to be able to readily and quickly clean the slide coating apparatus, in particular the cavities, for greater productivity of the coater facility. In operation, the separation and cleaning of the plates can be a time-consuming and cumbersome process. Typically, the plates are made of heavy-gauge metal and can be in the range of 12 inches to 120 inches wide in size, which precludes manual movement of the plates. Conventionally, the plates are separated from a coating position with a hand-crank mechanism which is bolted onto a side of the plates, and the crank mechanism is manually engaged. The procedure is then reversed when the plates are returned to the coating position. When the plates are particularly wide, a cranking mechanism is necessary on both sides of the plates, thus assuring essentially parallel separation of the plates, but adding to the time and effort required.
Therefore it is an object of this invention to provide an apparatus for moving one plate from an adjacent second plate and for returning the one plate in contact with the adjacent second plate in a slide coating apparatus.
It is another object of this invention to provide a method for separating plates in a slide coating apparatus whereby cleaning of the cavity areas is readily and quickly accomplished.